109 killers, 38 nonviolent offenders and 54 community controls were compared on psychiatric diagnosis, the MMPI, Cattell 16 PF, IQ and clinical neurological results. Killers did not differ from nonviolent offenders on diagnosis or personality in general. Only higher MMPI Hysteria scale scores differentiated the killers from the other groups. IQ tended to be lower and neurological findings more often positive in homicide cases than in controls. Results suggest that previous uncontrolled research on homicide has been misleading.